Int 2F Fn 1400  - European MS-dos 4.0 Popup - "checkpu" - Installation Ch  [D]

   AX = 1400h

Return: AX = FFFFh if installed
       BX = maximum memory required to save screen and keyboard info
   CF clear if successful
   CF set on error
       AX = error code
       0002h invalid function
       0004h unknown error

Note:  the POPUP interface is used by background programs (see INT 21/AH=80h)
     to communicate with the user

See Also: AX=1401h"POPUP",AX=1402h"POPUP",AX=1403h"POPUP"